Evaluation of Elements of New Propulsion Technology
for Littoral Combat Ships, LTS
It is described a novel combustion (AL/H2O) system and
high performance underwater jet engine for marine
propulsion based on the principle of the aeronautical
ramjet engine and drag reduction concept, providing, as
estimated, higher cruise speed (of about 100 knots) than
state-of the-art marine propulsion technology together
with simplicity, absence of moving underwater parts,
complicated gearboxes, etc., by removal of gas turbines,
diesel engine and props. The main elements of the
propulsion technology are:
1.
Al/H2O combustion activated by removal of Al oxides film
by wet machining or SFSW (Submerged Friction Stir
Welding) producing film-free surface and chips violently
reacting with water. The steam and other (mostly H2)
exhaust combustion products after production are directed
beneath the hull
2.
Friction drag reduction by using a part of exhaust products
for ¨steam and gas lubrication¨ of the hull
3.
The major part of exhaust products will be used to feed the
underwater jet propulsor unit consisting of a nozzle
assembly placed in the water under the vessel
V.I. Golovitchev and L. Montorsi
The movie (a clip from youtube.com)
of the modern LTS (Visby corvette): it
looks that the engine exhaust is not
directed beneath a hull, but cooled and
distributed along the ship boards
Fundamentals of Aluminum Combustion in Water
Aluminum has been selected as a perfect energy carrier.
The chemical energy is tightly ¨packed¨ in the molecules,
but Al is practically non-explosive. If aluminum is placed in
the water solution, combustion turns it into aluminum
hydroxide or oxide-hydroxides. The energy of this reaction
can be estimated as follows:
or finally,
that is equivalent to the aluminum combustion in oxygen.
Since the aluminum is covered by the oxides film, the last
one must be removed to initiate combustion. We proposed
a new way how to do this in the water stream.
V.I. Golovitchev and L. Montorsi
The movie (a clip from youtube.com) is
an illustration of Al/H2O combustion. In
this case, the aluminum-ice, ALICE,
slurry was used for rocket propulsion
as it proved at Purdue University.
Al/H2O Marine Propulsion System
Thermodynamic Analysis
Constant volume and energy problem
CONU
CONV
PRES 10.00 ! atm
TEMP 300.0 ! K
REAC AL
0.150
REAC H2O(L) 0.850
TEST 2000. ! K
END
INITIAL STATE:
P (atm)
1.0000E+01
T (K)
3.0000E+02
V (cm3/gm)
1.2715E+02
H (erg/gm)
-1.2542E+11
U (erg/gm)
-1.2671E+11
S (erg/gm-K) 2.5040E+07
W (gm/mole) 1.9360E+01
Combustion composition
EQUILIBRIUM STATE:
4.1329E+01
1.3403E+03
1.2715E+02
-1.2138E+11
-1.2671E+11
9.6512E+07
2.0930E+01
V.I. Golovitchev and L. Montorsi
Mole Fraction: initial
H2
0.0000E+00
O2
0.0000E+00
OH
0.0000E+00
H
0.0000E+00
H2O
0.0000E+00
O
0.0000E+00
H2O2
0.0000E+00
HO2
0.0000E+00
AL
1.5000E-01
AL2O3(S)
0.0000E+00
AL2O3(L)
0.0000E+00
Al2O3(g)
0.0000E+00
H2O(L)
8.5000E-01
products
2.4324E-01
5.5410E-15
7.0191E-09
1.5757E-07
6.7568E-01
4.1110E-15
2.3122E-14
2.8559E-17
1.1972E-19
7.7162E-02
3.9192E-03
3.3873E-32
1.5165E-21
Al/H2O Marine Propulsion System
Thermodynamic Analysis
Parametric Analysis of Combustion
a)
b)
a) Adiabatic flame temperature and b) fraction of hydrogen released by the aluminum
oxidation with water for different initial pressures
V.I. Golovitchev and L. Montorsi
Al/H2O Marine Propulsion System
a)
b)
Examples of wet a) SFW, b) grinding of Al ; after (I suggested in 1993) P.Fleming and K.Uehara et al.
V.I. Golovitchev and L. Montorsi
Al/H2O Marine Propulsion System
The sketch of the AL/H2O combustion chamber
a)
b)
a) View and b) concept behavior of a preliminary design of energy conversion system based
on the aluminum combustion in water: the oxide films are removed by machining
V.I. Golovitchev and L. Montorsi
Al/H2O Marine Propulsion System
Conventional vs. jet drive (The Pursuit Marine Drive, UK)
units comparison
V.I. Golovitchev and L. Montorsi
Al/H2O Marine Propulsion System
Tested jet drive unit configuration of the
Pursuit Marine Drive, UK
Steam and gas
Pursuit Marine Drive, UK, pump-jet unit,
Experimental set-up
V.I. Golovitchev and L. Montorsi
Pursuit Marine Drive, UK, pump-jet unit
operation driven by steam condensation
Hull Drag Reduction Concept by ¨Gas Lubrication¨
The schematic of the injection system on planing catamarans Cucci (1992)
V.I. Golovitchev and L. Montorsi
Hull Drag Reduction Concept by ¨Gas Lubrication¨
Table: Illustration of ¨gas lubrication¨ efficiency
The Table for different hulls was taken from ¨Ship hull drag
reduction using bottom air injection¨ by R. Latorre, Ocean Engng.,
vol, 24. 2, pp. 161-175, 1997
V.I. Golovitchev and L. Montorsi
Al/H2O Marine Propulsion System
Conclusions
 We propose to integrate all three elements of the
propulsion technology described above in a novel
configuration of the LCS with the high propulsion
efficiency and highly reduced vulnerability. The later
feature is achieved by a removal of attributes of
conventional marine propulsion system, i.e. jet
engines, and hydrocarbon fuel tanks (kerosene and
diesel oil) replaced by Al rods (or tubes)
V.I. Golovitchev and L. Montorsi